GENEVA (AP) -- The United Nations expects a cease-fire between Syrian troops and opposition forces to be in place no later than April 12, a spokesman for the U.N.-Arab League envoy Kofi Annan said Thursday, as activists reported a fierce attack by government troops on a Damascus suburb.
Kofi Annan's peace plan had previously set the April 10 deadline for Syrian troops to pull out of towns and cities, followed by a withdrawal by rebel fighters. Then all sides are supposed to hold talks on a political solution.
Annan's spokesman Ahmad Fawzi said they expect both sides to end the hostilities within 48 hours of the already agreed April 10 deadline.
"The clock starts ticking on the 10th for both sides to cease all forms of violence," he said.
Fawzi said that by then the Syrian military units should withdraw from populated centers and no new units should move into cities.
Syria has told U.N. officials that it is withdrawing troops from the southern province of Daraa, the northwestern province of Idlib and the rebel-controlled mountain resort town of Zabadani, north of Damascus, Fawzi said.
But activists in Syria said Syrian troops are attacking the Damascus suburb of Douma, in what they described as one of the most violent campaigns there since the year-old uprising began.
The attack on the suburb of Douma and other offensives around the country bolster the opposition's claim that President Bashar Assad's is only intensifying violence in the days before a deadline to implement a cease-fire. Activists say Assad wants to make gains on the ground before the truce is supposed to take effect.
Russia, meanwhile, said it could support a U.N. Security Council motion backing Annan's peace plan if it doesn't contain ultimatums to Bashar Assad's government.
Russia's Foreign Minister Sergey Lavrov didn't specify whether he was referring to a Council resolution or a statement, but warned that the document shouldn't contain any ultimatums or threats.
Russia has grown increasingly impatient with Assad, criticizing him for being slow at reforms and urging him to take the first step in implementing Annan's plan.
Lavrov's warning against the use of "any threats and ultimatums" in a U.N. motion backing Annan's plan indicated that Moscow will continue to protect Assad from foreign intervention.
Russia has vowed to block any U.N. resolution that could pave the way for a replay of what happened in Libya, where NATO action helped oust longtime dictator Moammar Gadhafi.